LiCl13 KCl eutectic salt waste including rare earth and TRU nuclides is produced in an electro refining process of spent oxide fuel. The reuse of the salt waste suddenly reduces an amount of waste to be finally processed, thereby very significantly affecting the excellence and economical efficiency of the electro refining process.
To reuse the salt waste, the nuclides (rare earth and TRU) included in the salt waste should first be separated. To this end, the related art has used a method of precipitating the nuclides into oxide by using oxidants Li2O, V2O5, etc., or precipitating them into carbonate or phosphate by adding precipitants Na2CO3, Li3PO4.
However, in the case of using the oxidants or the precipitants as in the related art, since it is difficult to separate the oxidants or the precipitants added above an equivalent and the eutectic compositions of LiCl—KCl are changed due to byproducts produced in oxidation reaction and precipitation reaction, it is very difficult to separate and reuse a pure LiCl—KCl eutectic salt.
Today, any other countries have not developed a reuse technology of the eutectic salt waste produced in the electro refining process; however, to reduce an amount of high-level radioactive waste to be finally processed, are developing a process of separating only the precipitates by precipitating the nuclides within the eutectic salt waste using the oxidants V2O5 and then distilling/condensing the entire eutectic salt waste. In this case, the entire eutectic salt waste should be distilled so that the operational costs of the distillation process are very high and the collected eutectic salt cannot be reused.
As a method of precipitating rare earth elements existing in the eutectic salt waste. A research result of using phosphoric acid Li3PO4 or oxidant Li2O has been published; however, it is difficult to reuse the eutectic salt even in the case of using this method.
In order to solve the aforementioned problems, the present provides a reuse apparatus of LiCl—KCl eutectic salt waste and a method thereof, which performs a layer separation into a pure salt layer and a precipitate layer by precipitating the nuclides including rare earth and TRU within the LiCl—KCl eutectic salt waste into oxide or oxychloride through a reaction with oxygen, without using the precipitants such as the oxidants, etc. and then separate the pure salt layer from the precipitate layer using siphons, and directly reuses the pure salt layer in the electro refining process and collecting and reusing the eutectic salt existing in the precipitate layer using volatilization and condensation processes.